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  #1  
Old 03-02-2012, 06:03 AM
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w123 240d problem after valve adjustment

Hi all, hope you can help...

I've got a 1981 240d with automatic transmission.
Valves hadn't been adjusted in too long, so I set about it (first time I've done this)...
Seemed to go fine: all the valves were too tight though, so adjusted to the recommended 0.1mm and 0.3mm.

Started the car back up, engine ran okay but: MUCH louder than before, gear shifts happen at much higher speed/revs than before, and the engine runs on a little after turning off the ignition.

Figured not all was well, left it overnight, checked again. All valves except 2 had slightly too much clearance, so readjusted until on the intake the 0.1 feeler will fit but not the 0.15, on exhaust the 0.3 will fit but not the 0.4 - I read somewhere that it's better to err on the loose side.

Ran the car again: a little quieter, but still noisier than before; engine still shifting far too late (eg. 58mph before it shifts into 4th - rev/speed limit for 3rd is 64mph), and still running on after the ignition is turned off - now for longer than before.

Any help much appreciated.
Thanks.

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  #2  
Old 03-02-2012, 09:19 AM
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Answer

Quote:
Originally Posted by theeb View Post
Hi all, hope you can help...

I've got a 1981 240d with automatic transmission.
Valves hadn't been adjusted in too long, so I set about it (first time I've done this)...
Seemed to go fine: all the valves were too tight though, so adjusted to the recommended 0.1mm and 0.3mm.

Started the car back up, engine ran okay but: MUCH louder than before, gear shifts happen at much higher speed/revs than before, and the engine runs on a little after turning off the ignition.

Figured not all was well, left it overnight, checked again. All valves except 2 had slightly too much clearance, so readjusted until on the intake the 0.1 feeler will fit but not the 0.15, on exhaust the 0.3 will fit but not the 0.4 - I read somewhere that it's better to err on the loose side.

Ran the car again: a little quieter, but still noisier than before; engine still shifting far too late (eg. 58mph before it shifts into 4th - rev/speed limit for 3rd is 64mph), and still running on after the ignition is turned off - now for longer than before.

Any help much appreciated.
Thanks.
A vacuum line is disconnected or broken.

Start by checking the BROWN tube on rear end of injection pump is connected.
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  #3  
Old 03-02-2012, 10:00 AM
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That could/would be the cause of all the symptoms that you are experiencing.
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  #4  
Old 03-02-2012, 10:06 AM
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As Hunter states the shift points where changed because of external engine issues. Changing the valve clearances themselves did not cause the higher shift points.

With proper valve clearances the engine may generate a little more noise as you have introduced clearance where there was much less. That portion could be considered normal I would expect.

Anyways it is much better to have proper valve clearances than not to. Believe me you will hear absolutly no differance at 70 miles per hour if you can hear yourself think at all.

Good practice if you found you had to move the adjustments quite a way to get normal clearances is to at least check the clearances again 500 miles later.

If you check and adjust where required every 15k miles from that point forward no recheck should be required. Too many of these cars have not had the clearances checked for far too long a time.

Consider checking out you fuel supply pressure at a future date on your 616 engine. That has nothing to do with your current post but is a wise thing to consider doing in my opinion.
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  #5  
Old 03-02-2012, 10:17 AM
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The change in shift points could be that you accidentally adjusted the bowden cable. I think your model has one. If so there is a linkage bracket on top of the valve cover that has a cable that goes down the the transmission. If so that's the bowden cable. You can turn the white adjusting nut to change the shift point. I can't remember which way will lower the shift points, but a search here will tell you.

I second, or third the vac line disconnected causing the shut off problem. Check all the lines in the engine bay. You may have damaged one of the ports on the main vac line or just simple knocked one of the lines off.

Welcome to the forum by the way!
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Last edited by Biodiesel300TD; 03-02-2012 at 11:35 AM.
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  #6  
Old 03-02-2012, 10:29 AM
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Quote:
Originally Posted by Biodiesel300TD View Post
The change in shift points could be that you accidentally adjusted the bowden cable. I think your model has one. If so there is a linkage bracket on top of the valve cover that has a cable that goes down the the transmission. If so that's the bowden cable. You can turn the white adjusting nut to change the shift point. I can't remember which way will lower the shift points, but a search here will tell you.
Beat me to it. Same thing happened to me the first time I adjusted the valves. I had to readjust the bowden cable after driving it after the valve adjustment.
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  #7  
Old 03-02-2012, 11:29 AM
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There is no bowden cable on a 1981 240D, it is vacuum-only, so if you knock off a vacuum cable, it will only shift at high speeds.
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  #8  
Old 03-02-2012, 11:36 AM
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Quote:
Originally Posted by Govert View Post
There is no bowden cable on a 1981 240D, it is vacuum-only, so if you knock off a vacuum cable, it will only shift at high speeds.
Thanks, I can never remember when MB starting using the bowden cable, my 82 had one.
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  #9  
Old 03-02-2012, 02:09 PM
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Wow - thanks for all the help. Only just joined the forum, and that's a great welcome...

Yep, vacuum line had popped out! Feel like a bit of an idiot - though in my defence this is my first diesel, and first automatic... Having reconnected it though, while a vast improvement, the shifts do not seem entirely regular - sometimes it feels like I'm only going through 3 gears, skipping over 3rd and straight to 4th....

Having had a closer look at the vacuum line arrangements, I think something may be missing on my engine: every picture and diagram I have found seems to have at least one more 3-way connector than I do...my surge damper - I think that's what it is...stubby green cylinder with tube coming off either side? - is not connected to any other line...and I'm a little confused by functioning of the 3-tube switch connected to the throttle linkage...

Has anyone got good photos or a definitive diagram of their set-up for a 240d automatic. I've had contradictory results searching for one..?

Good news however - because it's been running with the present set-up for at least 15 or 20 000 miles, and the shifting is functional, if not perfect, I figured I'd give her a post-valve-adjustment run...all was very smooth, and my mpg went from a pre-treatment 26ish to a scarcely credible 38!
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  #10  
Old 03-02-2012, 03:52 PM
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Very impressive. You will find that taking a few pictures before work is started can be incredibly helpful.

Im sure some 240D pics will popup for you soon.
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  #11  
Old 03-05-2012, 02:28 AM
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anybody??
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  #12  
Old 03-05-2012, 02:39 AM
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Vacuum diagrams of the EGR are in the FSM:

14 Intake Manifold, Exhaust Manifold, Emissions Control System - OM616

There 14-050

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